1 files changed, 90 insertions, 0 deletions
diff --git a/apps/web/src/lib/fonts/google-fonts.ts b/apps/web/src/lib/fonts/google-fonts.ts
new file mode 100644
index 00000000..7e55dffd
--- /dev/null
+++ b/apps/web/src/lib/fonts/google-fonts.ts
@@ -0,0 +1,90 @@
+import type { FontAtlas } from "@/types/fonts";
+import { SYSTEM_FONTS } from "@/constants/font-constants";
+
+const GOOGLE_FONTS_CSS = "https://fonts.googleapis.com/css2";
+
+const fullLoaded = new Set<string>();
+
+let cachedAtlas: FontAtlas | null = null;
+let atlasFetchPromise: Promise<FontAtlas | null> | null = null;
+
+function encodeFamily(family: string): string {
+	return family.replace(/ /g, "+");
+}
+
+export function getCachedFontAtlas(): FontAtlas | null {
+	return cachedAtlas;
+}
+
+export function clearFontAtlasCache(): void {
+	cachedAtlas = null;
+	atlasFetchPromise = null;
+}
+
+async function fetchAtlas(): Promise<FontAtlas | null> {
+	if (cachedAtlas) return cachedAtlas;
+	if (atlasFetchPromise) return atlasFetchPromise;
+
+	atlasFetchPromise = fetch("/fonts/font-atlas.json")
+		.then(async (response) => {
+			if (!response.ok) return null;
+			const data: FontAtlas = await response.json();
+			cachedAtlas = data;
+			return data;
+		})
+		.catch(() => null);
+
+	return atlasFetchPromise;
+}
+
+function preloadChunkImages({ atlas }: { atlas: FontAtlas }): void {
+	const maxChunk = Math.max(
+		...Object.values(atlas.fonts).map((entry) => entry.ch),
+	);
+	for (let i = 0; i <= maxChunk; i++) {
+		const img = new Image();
+		img.src = `/fonts/font-chunk-${i}.avif`;
+	}
+}
+
+export function prefetchFontAtlas(): Promise<FontAtlas | null> {
+	return fetchAtlas().then((atlas) => {
+		if (atlas) preloadChunkImages({ atlas });
+		return atlas;
+	});
+}
+
+export async function loadFullFont({
+	family,
+	weights = [400, 700],
+}: {
+	family: string;
+	weights?: number[];
+}): Promise<void> {
+	if (fullLoaded.has(family)) return;
+
+	const url = `${GOOGLE_FONTS_CSS}?family=${encodeFamily(family)}:wght@${weights.join(";")}&display=swap`;
+	const link = document.createElement("link");
+	link.rel = "stylesheet";
+	link.href = url;
+	document.head.appendChild(link);
+	await new Promise<void>((resolve) => {
+		link.addEventListener("load", () => resolve(), { once: true });
+		link.addEventListener("error", () => resolve(), { once: true });
+	});
+	await Promise.all(
+		weights.map((weight) =>
+			document.fonts.load(`${weight} 16px "${family.replace(/"/g, '\\"')}"`),
+		),
+	);
+	fullLoaded.add(family);
+}
+
+export async function loadFonts({
+	families,
+}: {
+	families: string[];
+}): Promise<void> {
+	const googleFonts = families.filter((family) => !SYSTEM_FONTS.has(family));
+	await Promise.all(googleFonts.map((family) => loadFullFont({ family })));
+}